1. Field of the Invention
The present invention relates to a medical device capable of turning a direction of a function portion provided at a distal end of an insertion portion by a predetermined angle with respect to the insertion portion.
2. Description of Related Art
In recent years, an endoscope is widely used in the medical field. An endoscope includes an elongated insertion portion and an operation portion provided at a proximal end of the insertion portion. Generally, the elongated insertion portion has a distal end to which a bendable bending portion is provided. The operation portion is provided with, for example, a knob for operating and bending the bending portion, various switches for functioning various operations of the endoscope, a treatment instrument introducing port for inserting a treatment instrument for endoscope (hereinafter referred to as a treatment instrument) into a treatment instrument channel.
An endoscope used in the medical field includes an insertion portion which is inserted into a body cavity of a subject for observation of organs in the body cavity. Furthermore, in such an endoscope, the insertion portion is provided with a treatment instrument channel through which a treatment instrument is introduced into the body cavity, and it is possible to perform various treatments, inspections, and the like using the treatment instrument.
The treatment instrument generally includes an operation portion positioned at a hand-side, an insertion portion extended from the operation portion, and a function portion (also described as a treatment portion) provided at a distal end of the insertion portion. As such a treatment instrument, there are a treatment instrument such as an injection needle which can be used without a work for adjusting a direction of the function portion with respect to a site to be treated before a treatment, and a treatment instrument such as a biopsy forceps, a papillotomy knife, and the like, which requires a work for adjusting a direction of the function portion within a possible range with respect to the site to be treated before the treatment.
That is, when the biopsy forceps is extracted into a body cavity from the treatment instrument channel, in a case where an opening/closing direction of a biopsy cups is inconvenient with respect to a site to be treated, the direction is adjusted by turning the biopsy cups.
Methods for turning a function portion of a treatment instrument are disclosed in Japanese unexamined patent publication No. 2005-34623, U.S. Pat. No. 5,439,478, U.S. Pat. No. 6,027,522, and the like.
In the method disclosed in Japanese unexamined patent publication No. 2005-34623, the insertion tube inserted in the covering tube is turned by turning the operation portion, and the treatment portion is turned by turning the insertion tube. That is, the insertion tube is a turning force transmitting member for transmitting a turning force to turn the treatment portion.
On the other hand, in the methods disclosed in U.S. Pat. No. 5,439,478 and U.S. Pat. No. 6,027,522, the treatment portion is turnable with respect to the insertion portion, and the treatment portion is turned by turning a driving wire. That is, the driving wire is a turning force transmitting member for turning the treatment portion.
When an operator adjusts a direction of the function portion of the treatment instrument during an operation, the operator adjusts the direction by turning a turning force transmitting member located on a hand-side of the treatment instrument. The treatment instrument has flexibility so as to be able to be inserted into a treatment instrument channel provided in the elongated flexible insertion portion of the endoscope. A turning force transmitting performance of the turning force transmitting member provided to the treatment instrument is influenced by flexibility, and the turning force transmitting performance generally degrades by improving flexibility.
When the function portion provided at a distal end of the turning force transmitting member is turned by turning a hand-side of the turning force transmitting member having a poor turning force transmitting performance, in other words, having a high flexibility, twist generated in the turning force transmitting member due to the turning of the hand-side thereof is accumulated. Then the twist is released at once, so that the function portion is turned. That is, in the turning force transmitting member with poor turning force transmitting performance, the turning of the hand-side thereof is not directly transmitted to the distal end, so that it is difficult to stop the turning of the function portion in a desired direction.
Therefore, when adjusting the direction of the function portion by turning the turning force transmitting member having poor turning force transmitting performance, the operator seldom succeeds in adjusting the direction of the function portion in a desired direction by a first turning operation. The operator usually repeats the turning operation a plurality of times in order to adjust the direction of the function portion in an almost desired direction. Note that a turning force transmitting member having flexibility and rich turning force transmitting performance is expensive, and this is one reason why the treatment instrument becomes expensive.